games with installers dont use up much more time than uncompressing a zipped folder,
but its easier to delete a folder than it is to uninstall a game, and sometimes the shortcuts are still there somewhere.
Despite the people who don't like them, I would still use installers.
1. They look professional
2. They're useful for people who *don't* have MMF already installed
3. The registry alterations you can perform save on having them scripted into your application (eg: assigning file types with more shell customisation)
4. They irritate clickers, which is always a bonus
5. They integrate their uninstal apps into Add/Remove Programs <-- again useful for non-clickers.
If you really want class in your games, though, you could always go a step further. Build the installer in MMF too, and have the game data and necessary DLLs built into the exe (using the Project Builder in MMF1.5).
This way, you get an entirely *customised* instal program that looks professional, edits the registry smoothly, works for people who don't have MMF, and irritates clickers.